The purpose of this study is to assess the relationship between plasma cholecystokinin levels and chronic pancreatitis. Obstructed pancreatic ducts may result in elevated CCK levels since CCK is an important mediator in the feedback control of pancreatic secretion. If elevated CCK levels were a marker of a physiologically obstructed pancreatic duct, this might in turn indicate that decompression of the pancreatic duct should be performed in this select group of patients.